SPC 2000Z Day 1 Outlook
Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
0226 PM CDT Wed Jun 01 2022
Valid 012000Z - 021200Z
...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF
THE SOUTHERN GREAT PLAINS INTO THE MID SOUTH...OHIO VALLEY AND PARTS
OF THE NORTHERN MID ATLANTIC COAST STATES...
...SUMMARY...
Scattered strong to severe thunderstorms are possible into this
evening in a narrow corridor extending from southern portions of the
Great Plains into the Mid South, Ohio Valley and northern Mid
Atlantic region. Some of these will pose a risk for producing
mainly severe wind and hail.
...20z Update...
The main change for the 20z update was to extend the Slight risk and
corresponding SIG wind and hail probabilities westward across small
portion of southeast NM and far west TX. Moderate effective shear
will overlap with a strongly unstable airmass supporting initial
high-based supercell activity this afternoon in a weak low-level
easterly upslope flow regime. With time, any more discrete
convection will develop into eastward propagating clusters via
outflow interactions. Isolated wind gusts of 65-80 mph will be
possible, in addition to sporadic 2+ inch hail.
The Slight and Marginal risk areas were trimmed across Oklahoma
based on latest observations and outflow position. Other minor
adjustments of the Slight risk area across the Mid-South is based on
latest CAMs guidance and forecast soundings indicating weakening of
any convection as it spreads into these areas later this evening.
Areas across the Ohio Valley and Northeast where Severe Thunderstorm
Watch 301 in ongoing have remained unchanged with the 20z update.
..Leitman.. 06/01/2022
.PREV DISCUSSION... /ISSUED 1110 AM CDT Wed Jun 01 2022/
...Synopsis...
Blocking has become more prominent to the east of the Canadian/U.S.
Rockies, with a mid-level high now centered east-northeast of Hudson
Bay and a pair of more notable mid-level lows centered either side
to its south, offshore of the Canadian Maritimes and southwest of
Hudson Bay. A modest belt of westerlies lingers to the south of
this regime, to the north of mid-level subtropical ridging which
will be maintained across much of the Gulf Coast states and Gulf of
Mexico, though a weak embedded mid-level low persists to the
north-northeast of the Bahamas.
Seasonably mild to cool near-surface air associated with the
mid-level lows has infiltrated much of the northern through south
central Great Plains, upper half of the Mississippi Valley and New
England. The front across the southern Great Plains into Great
Lakes is preceded by multiple outflow boundaries, with the front and
conglomerate outflow forecast to advance southward through much of
the Ohio and Tennessee Valleys and a bit farther southward across
the mid to lower Mississippi Valley and southern Great Plains
through daybreak Thursday.
The boundary layer to the south of the front and outflow remains
seasonably moist and continues to moisten further, which will likely
contribute to moderately large CAPE with daytime heating. While the
boundaries have become increasingly displaced to the south of the
stronger but weakening mid/upper westerlies, deep-layer shear may
still be marginally sufficient to support occasional organized storm
structures and organizing storm clusters anywhere from the southern
Great Plains through the Mid South and Ohio Valley into the northern
Mid Atlantic states.
...Southern Great Plains into northern Mid Atlantic...
A number of weak mid/upper perturbations, some convectively
generated, along the southern fringe of the westerlies may
contribute to renewed thunderstorm development and intensification
as the boundary layer destabilizes by mid to late afternoon. This
will be mostly focused in a relatively narrow corridor near/just to
the south of the front/outflow. Deep-layer mean wind fields may be
somewhat stronger across parts of the upper Ohio Valley into the
northern Mid Atlantic states, while lower/mid tropospheric lapse
rates will be generally steeper across the southern Great Plains
into the Red River Valley. However, in the mean, similar severe
weather potential may exist across most areas, with organizing storm
clusters capable of producing severe wind and hail possible this
afternoon into tonight.
Read more CHECK UPDATE ZOOM GRAPHIC
http://dlvr.it/SRSjzf
